The remoteness of the Channel Islands create a haven for nesting seabirds. From migratory birds who use the islands as a stopover to year-round residents, the Santa Barbara Channel is home to a rich variety of seabirds.
Trends in seabird abundance
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Trends in seabird abundance and the relative abundance of krill and forage fish, based on CalCOFI/CCE LTER program data (1987–2011). Spring and summer seabird density declined by 2 percent per year, mostly in the northern sector of the study region. Krill showed variable trends. Nearshore forage fish, dominated by northern anchovy, and offshore mesopelagic species show declines in relative abundance over this period. Figure: Sydeman et al. 2015
Seabirds - species richness map
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Seabird species richness spatial anomalies (A,C) and persistence of hotspots (B,D) based on visual survey for seabirds during spring and summer CalCOFI surveys from 1987 to 2012. A spatial anomaly was computed from the grand spatial mean and standard deviation for each block. Cool colors denote blocks below the mean and warm colors denote blocks above. Higher species richness and hotspot persistence (red, yellow) is observed along the coast and around Channel Islands compared to offshore (blue). Seabird species richness calculations based on 68 species/taxa. Figure: Santora and Sydeman 2015
Seabirds - species richness trends
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Change over time in seabird species richness anomaly (i.e., number of species observed per survey compared to the long-term average) based on visual survey of seabird distribution and abundance during CalCOFI spring and summer surveys since spring 1987. Seabird species richness has exhibited a long-term decline in the CalCOFI region, and has been negative since 2013. The decline in species richness possibly indicates that biophysical changes occurring in the southern California Current is impacting the overall at-sea seabird community. Figure: Leising et al. 2015